Crossed-grid electroluminescent phosphor illumination control element



May 4, 1965 J. T. M NANEY 3,182,199

CROSSED-GRID ELECTROLUMINESCENT PHOSPHOR ILLUMINATION CONTROL ELEMENTFiled Aug. 1, 1962 I NVENTOR.

United States Patent 3,182,199 CRGSSED-G ELECTROLUMINESCENT PHOS- PHORILLUMINATION CONTROL ELEMENT Joseph T. McNaney, 8548 Boulder Drive, LaMesa, Calif. Filed Aug. 1, 1962, Ser. No. 213,937 8 Claims. (Cl. 250213) This invention relates to crossed-grid electroluminescent phosphorillumination control elements of a type which lends itself to thefabrication of closely packed arrays wherein an array of N on-oifcontrol elements may be controlled by 2N input functions. Moreparticularly, however, this invention relates to control elements whichare designed to radiate predetermined colors in response topredetermined input functions.

Closely packed panel-like arrays of these control elements will providedisplays of pictorial data under the control of electronic computergenerated data, or, in response to signal information being derived fromcommercial or closed-circuit TV programs.

Developments of display panels around the use of an electroluminescentphosphor have resulted in a variety of means for subjecting selectedareas of a layer of phosphor to the excitation forces of an electricfield. But the simplest of these will be found in the crossed-gridtypes. These consist of a layer of electroluminescent phosphor embeddedin a suitable dielectric, sandwiched between a series of parallelconductors on one side and a 90 displaced series of parallel conductorson the opposing side.

Such an arrangement of X-Y conductors lends itself to applying a voltageto a single pair of X-Y conductors, subjecting the phosphor to anelectric field in an area which coincides with the crossover point ofthe two conductors. Due to the effects of capacitive coupling betweenadjacent parallel conductors the electric field will be extended beyondthe cross-over point of the two energized conductors. Under suchconditions a much larger area of the phosphor will be excited which, ofcourse, results in very poor picture resolution and also brightness, dueto the undesirable spreading of light about the area immediatelyadjacent the crossover point of the initial pair of conductors.

This difiiculty with the crossed-grid type of display panel have ledtothe development of other types of display panels which involve the useof an array of individual phosphor area control elements. The elementsused in these developments are well known in the art as nonlinearferroelectric capacitors, transfluxors, and other similar devices.Although panels using such elements have been shown to have very goodlight output and contrast ratio, they are extremely complex whencompared with the relatively simple crossed-grid display panel. Sinceresolution appears to be a major problem, the use of ferrorelectriccapacitors, transiluxors, and the like, seem to be limited to largescreen displays.

An important object of the present invention is to improve on therelatively simple crossed-grid display panel approach by overcoming thecapacitive coupling difficulties responsible for poor picture resolutionand picture brightness.

It is therefore an object of this invention to incorporate the use oflight conductor means in combination with photoconductive materials toprovide an array of individual phosphor area control elements which lendthemselves to the fabrication of either small or large screen displays.

A further object is to provide a crossed-grid electroluminescentphosphor illumination control element which is 1designed to providelight radiation of a predetermined co or.

Other objects and advantages of the invention will become apparent fromthe following description when taken in conjunction with theaccompanying drawing wherein an individual control element is shownwhich embodies the basic concepts of the invention. 7

Referring now to the invention as illustrated, it is comprised of aplurality of first electrodes 2, 3 and 4, a plurality of layers ofelectroluminescent phosphor 5, 6 and 7, a second electrode 8,photoconductive material 9, and light conductor means 19 for conductinglight to the photoconductive material 9. A source of electrical power 11is provided. One terminal 12 is connected to the second electrode 8through an on-oif switch 13. An opposite terminal 14 is connected to thefirst electrodes 2, 3 and 4 through separate variable resistors 15, 16and 17 The first electrodes 2, 3 and 4 are longitudinally ex tendingelectrical conductors and preferably optically transparent. An exampleof a well known material that may be used for thispurpose is aconductive material produced by Pittsburgh Plate :Glass Co., under thetrademark NESA transparent conductive material.

The electroluminescent phosphor 5, 6 and '7 is illustrated as beingcomprised of three longitudinally extending layers each having dilferentcolor emission characteristics. For example, the layers 5, 6 and 7 maybe made to emit, respectively, red, blue and green. However, the layers5, 6 and 7 may all be made to emit the same color, or, merely whitelight. In either event the electroluminescent phosphor is embedded in asuitable dielectric and intimately joined with the first electrodes 2, 3and 4.

The photoconductive material 9 may be selected from among certainmaterials such as selenium, cadmium sulphide, silver selenide,germanium, and like materials, each of which have properties which intotal darkness cause the material to be an excellent resistor toelectric current, while in the presence of light the material becomesconductive.

The light conductor means Iii may be made from such materials as quartz,glass, Lucite, nylon or other similar materials. The light conductormeans It) is longitudinally extending and displaced approximately orless, with respect to the longitudinally extending electrodes 2, 3 and.4, and is spaced apart therefrom. It is preferably a light conductingfiber having a predetermined index of refraction and a light conductingjacket 20 having an index of refraction less than said predeterminedindex. The jacket 20 is adapted to control the reflection of lightthrough the fiber 10 and the reflection of light to the photoconductivematerial 9.

The second electrode 5' is a longitudinally extending electricalconductor spaced apart from the phosphor layers 5, 6 and '7, and isparallel therewith. The photo.- conductive material 9 in the spacedapart dimension is connected operatively with the second electrode 8 andthe phosphor layers 5, .6 and 7, and intimately joined with the lightconduct-or means it The spaced apart dimension 19 between the firstelectrodes 2, 3 and 4, and the second electrode 8 is sufficiently greatenough to avoid any excitation of the phosphor layers 5, 6 and 7 whilethe photoconductive material 9 is in a state of darkness and while theinfluence of electrical potentials are across a the phosphor 5, 6 and 7and the photoconductive material 9.

When placed in operation the control unit as illustrated will besubjected to potentials from the source of electrical power 11, and asource of light entering the light conductor means in the direction ofarrow 21. Under these conditions light radiation from the phosphorlayers 5, 6 and 7 will be viewed from the direction of arrow 22. If, forexample, the layers 5, 6 and 7 are designed to emit red, blue and greenlight respectively, a wide range of color combinations may be viewedfrom the direction of arrow 22 in response to a similarly wide range ofadjustments made to the variable resistors 15, 16 and 17, and upon theclosing of the on-off switch 13, and the admission of light to the lightconductor means 10.

Although the photoconductive material 9 presents a high degree ofresistance to the flow of electrical current when in a state of darknessand a relatively low amount of resistance when exposed to light, thevoltage drop across the material 9 between the phosphor and theelectrode 8 may be regulated as a function of light intensity enteringthe light conductor means 10. The intensity of light radiation from thephosphor layers 5, 6 and 7 may, therefore, be under the control of lightentering the conductor means 10, while the color of said light radiationis being controlled as a function of the adjustments made to thevariable resistors 15, 16 and 17.

Although the invention as illustrated includes the use of but a singlelight conducting fiber 10, it should, of course, be understood that twoor more such fibers of smaller cross sectional dimensional may beutilized within the same space being occupied by the fiber 10. It iswell known in the arts that such light conductor means 10 may be made offibers equal to 0.001 in diameter, or less. Light conducting fibersdesigned to control the illumination of photoconductive materialintimately joined therewith are disclosed and patented in my US. PatentsNo. 3,047,867 and No. 3,050,623.

Large numbers of the control elements may be assembled in panel-likearrays wherein an array of N control elements may be controlled by 2Ninput functions. In display panel arrays such as this a plurality oflongitudinally extending light conductor means 10 may be arranged inwhat is termed as X-control positions, and a combination of the firstand second longitudinally extending electrodes may be duplicated andarranged in what is termed as Y-control positions. At each crossing ofthe light conductor means and the electrodes the photoconductivematerial will be allowed to function as a switch through which thephosphor associated therewith will be energized.

I have chosen to show a source of potential 11, an on-otf switch 13, andvariable resistors 15, 16 and 17 as a means of presenting a potentialinfluence across the phosphor layers 5, 6 and 7 and the photoconductivematerial 9. It should, of course, be understood that similar controlvoltages may be derived from a number of other means that are well knownto those skilled in the art. Light information being admitted to thelight conductor means 10 may be derived from any one of numerous typesof light wave generators, such as from cathode ray tubes,electroluminescent phosphor light generators, or the like.

Although I have limited myself to the showing of but one designconfiguration it should be understood by those skilled in the arts thatthe invention is not limited in this regard. For example, withoutdeparting from the invention, the three longitudinally extendingelectrodes 2, 3 and 4 may take the form of a single electrode, and thethree individual layers of phosphor 5, 6 and 7 may be but a single layerdesigned to emit white light. Such a control element could be utilizedin a greatly simplified array for merely black and white pictorialdisplays. It should also be understood that many of the otherembodiments embracing the general principles and constructionshereinbefore set forth, may be utilized and still be within the ambit ofthe present invention.

The particular embodiment of the invention illustrated and describedherein is illustrative only, and the invention includes such othermodifications and equivalents as may readily appear to those skilled inthe arts, and within the scope of the appended claims.

I claim:

1. A crossed-grid electroluminescent phosphor illumination controlelement comprising:

(a) a plurality of longitudinally extending first electrodes;

(b) longitudinally extending light conductor means angularly displacedwith respect to said longitudinally extending first electrodes, spacedapart therefrom and defining a crossing therebetween;

(c) photoconductive material presenting first and second lightresponsive portions, said first portion being intimately joined withsaid light conductor means coincident with said crossing and adapted toreceive light from said light conductor means;

(d) electroluminescent phosphor intermediate said material and saidfirst electrodes;

(e) a second electrode spaced apart from said phosphor and connectedelectrically with said material;

(f) means for presenting the influence of a combination of electricalpotentials across said phosphor and said material intermediate saidfirst electrodes and said second electrode; and means for deriving lightradiation from said phosphor corresponding to said combination ofelectrical potentials upon the admission of light to said lightconductor means;

(g) light control means intermediate the second portion of said materialand said light conductor means for light insulating said second portionfrom said light conductor means; and

(h) means for exposing the second portion of said material to said lightradiation from said phosphor.

2. A crossed-grid electroluminescent phosphor illumination controlelement comprising:

(a) a plurality of longitudinally extending first electrodes;

(b) longitudinally extending light conductor means angularly displacedwith respect to said longitudinally extending first electrodes, spacedapart therefrom and defining a crossing therebetween;

(c) photoconductive material presenting first and second lightresponsive portions, said first portion being intimately joined withsaid light conductor means coincident with said crossing and adapted toreceive light from said light conductor means;

(d) a plurality of layers of electroluminescent phosphor havingdifferent color emission characteristics intermediate, respectively,said plurality of first electrodes and said material;

(e) a second electrode spaced apart from said phosphor and operativelyjoined with said material;

(1) means for presenting the influence of a combination of electricalpotentials across said phosphor and said material intermediate saidfirst electrodes and said second electrode; and means for deriving fromsaid phosphor a combination of colors corresponding to said combinationof electrical potentials upon the admission of light to said lightconductor means;

(g) light control means intermediate the second portion of said materialand said light conductor means for light insulating said second portionfrom said light conductor means; and

(/1) means for exposing the second portion of said material to saidcombination of colors from said phosphor.

3. A crossed-grid electroluminescent phosphor illumination controlelement comprising:

(a) a layer of photoconductive material presenting first and secondlight responsive portions;

(b) a first light conductor means having a predetermined index ofrefraction for supporting said material and conducting light to thefirst portion of said material;

(c) a second light conductor means having an index of refraction lessthan said predetermined index jacketing said first light conductor meansfor controlling the reflection of light through said first lightconductor means and the reflection of light to the first portion of saidmaterial while preventing the exposure of the second portion of saidmaterial;

(d) a plurality of layers of electroluminescent phosphor havingdifferent color emission characteristics adjacent said material;

(2) means for presenting the influence of electrical potentials acrosssaid phosphor and said material; and

(f) means for deriving light radiation from said phosphor upon thereflection of light from said second light conductor means to the firstportion of said material.

4. An array of electroluminescent phosphor illumination control elementscomprising:

(a) a plurality of longitudinally extending first electrodes;

(b) a plurality of longitudinally extending layers of electroluminescentphosphor joined, respectively, with said plurality of first electrodes;

(c) a plurality of longitudinally extending light conductor meansangularly displaced with respect to said longitudinally extending firstelectrodes, spaced apart therefrom and defining between them a pluralityof crossings;

(d) photoconductive material presenting first and second lightresponsive portions, intermediate said light conductor means and saidphosphor coincident with said crossings and said first portion beingadapted to receive light from said light conductor means and said secondportion being adapted to receive light from said phosphor;

(e) a second electrode spaced apart from said phosphor and connectedelectrically with said material. 5. An electroluminescent phosphor datadisplay panel comprising:

(a) a plurality of longitudinally extended light conductor means eachhaving a predetermined index of refraction andlight reflector meansadapted to control the reflection of light Waves through said lightconductor means;

(b) a plurality of longitudinally extended layers of electroluminescentphosphor angularly displaced With respect to said light conductor meansand defining between them a plurality of crossings;

(c) photoconductive material presenting first and second lightresponsive portions and said first portion being intimately joined withsaid light conductor means and said phosphor coincident with said crossings;

(d) means for presenting the influence of electrical potentials acrosssaid phosphor and said material selectively and at predeterminedcrossings of said light conductor means and said phosphor;

(e) means for presenting light selectively to said light conductormeans; and

(1) means for deriving light radiation from said phosphor atpredetermined crossings of said light conductor means and said phosphor;

(g) said light reflector means being adapted to light insulate thesecond portion of said material from said light conductor means; and

(h) said second portion of said material being adapted to receive saidlight radiation.

6. An electroluminescent phosphor illumination control data displaypanel comprising:

(a) a plurality of light conducting fibers each having a predeterminedindex of refraction and a light conducting jacket having an index ofrefraction less than said predetermined index;

(b) a plurality of electrical conductors angularly displaced withrespect to said fibers, spaced apart therefrom and defining between thema plurality of crossings;

(c) photoconductive material presenting first and second lightresponsive portions, disposed upon said fibers coincident with saidcrossings;

(d) said fibers being adapted to control the conduction of light to thefirst portion of said material and said jacket being adapted to lightinsulate the second portion of said material from said fibers andcontrol the reflection of light through said fibers to the first portionof said material;

(e) electroluminescent phosphor intermediate said photoconductivematerial and predetermined electrical conductors coincident with saidcrossings and intimately joined with said material and said conductors;

(f) an electrode spaced apart from said phosphor and connectedelectrically with said photoconductive material;

(g) said electroluminescent phosphor comprising a plurality ofindividual layers having different color emission characteristics;

(h) means for presenting the influence of a combination of electricalpotentials across said individual layers and said photoconductivematerial at predetermined crossings; and

(i) means for deriving light radiation from said individual layers at apredetermined crossing and of a predetermined color upon the admissionof light to predetermined light conducting fibers;

(i) said second portion of said material being adapted to receive saidlight radiation from said layers.

7. A crossed-grid electroluminescent phosphor illumination controlelement comprising:

(a) first and second longitudinally extending parallel electrodessupported in a spaced apart relationship;

(b) at least one longitudinally extending light conductor meansintermediate said first and second electrodes, angularly displaced withrespect to said first and second electrodes and defining between them acrossing;

(c) a layer of electroluminescent phosphor intimately joined with saidfirst electrode coincident with said crossing;

(d) photoconductive material presenting first and second lightresponsive portions intermediate said phosphor and said second electrodeand connected electrically therewith, and the first portion of saidmaterial being intimately joined with said light conductor meanscoincident with said crossing;

(e) light control means intermediate the second portion of said materialand said light conductor means for light insulating said second portionfrom said light conductor means.

8. A crossed-grid electroluminsecent phosphor illumination, controlelement comprising:

(a) first and second longitudinally extended parallel electrodes indiiferent planes;

(b) at least one longitudinally extended light conducting fiberintermediate said first and second electrodes defining a crossingbetween said fiber and said electrodes;

(c) a layer of electroluminescent phosphor joined operatively with saidfirst electrode coincident with said crossing;

(d) photoconductive material presenting first and second lightresponsive portions intermediate said phos- 7 phor and said secondelectrode and connected electrically therewith;

(c) said light conducting fiber optically connected to said material forthe conduction of light to the first portion of said material coincidentwith said crossing; and

(f) light reflector means intimately joined to said fiber forcontrolling the reflection of light through said fiber and to the firstportion of said material while References Cited by the Examiner UNITEDSTATES PATENTS Loebner 250-213 Nicoll 250-213 X McNaney 250-227 XLempicki 250-213 Kaisler et a1. 250-227 McNaney 250-213 preventing theexposure of the second portion of 10 RALPH NILSON, Primary ExaminerARCHIE R. BORCHELT, Examiner.

said material.

1. A CROSSED-GRID ELECTROLUMINESCENT PHOSPHOR ILLUMINATION CONTROLELEMENT COMPRISING: (A) A PLURALITY OF LONGITUDINALLY EXTENDING FIRSTELECTRODES; (B) LONGITUDINALLY EXTENDING LIGHT CONDUCTOR MEANS ANGULARLYDISPLACED WITH RESPECT TO SAID LONGITUDINALLY EXTENDING FIRSTELECTRODES, SPACED APART THEREFROM AND DEFINING A CROSSING THEREBTWEEN;(C) PHOTOCONDUCTIVE MATERIAL PRESENTING FIRST AND SECOND LIGHTRESPONSIVE PORTIONS, SAID FIRST PORTION BEING INITIMATELY JOINED WITHSAID LIGHT CONDUCTOR MEANS CONICIDENT WITH SAID CROSSING AND ADAPTED TORECEIVE LIGHT FROM SAID LIGHT CONDUCTOR MEANS; (D) ELECTROLUMINESCENTPHOSPHOR INTERMEDIATE SAID MATERIAL AND SAID FIRST ELECTRODES; (E) ASECOND ELECTRODE SPACED APART FROM SAID PHOSPHOR AND CONNECTEDELECTRICALLY WITH SAID MATERIAL; (F) MEANS FOR PRESENTING THE INFLUENCEOF A COMBINATION OF ELECTRICAL POTENTIALS ACROSS SAID PHOSPHOR AND SAIDMATERIAL INTERMEDIATE SAID FIRST ELECTRODES AND SAID SECOND ELECTRODE;AND MEANS FOR DERIVING LIGHT RADIATION FROM SAID PHOSPHOR CORRESPONDINGTO SAID COMBINATION OF ELECTRICAL POTENTIALS UPON THE ADMISSION OF LIGHTTO SAID LIGHT CONDUCTOR MEANS; (G) LIGHT CONTROL MEANS INTERMEDIATE THESECOND PORTION OF SAID MATERIAL AND SAID LIGHT CONDUCTOR MEANS FOR LIGHTINSULATING SAID SECOND PORTION FROM SAID LIGHT CONDUCTOR MEANS; AND (H)MEANS FOR EXPOSING THE SECOND PORTION OF SAID MATERIAL TO SAID LIGHTRADIATION FROM SAID PHOSPHOR.